The present invention relates generally to truck mounted equipment for the loading, transport and unloading of large articles. The present invention specifically pertains to that type of apparatus for loading and unloading of an upright article which is tipped on its side for transport from a loading to an unloading site.
A large monolithic structure such as a concrete pipe section is particularly cumbersome to load and transport for obvious reasons. Commonly, costly motorized cranes are utilized in the removal of such conduit from its casting site in a plant to a storage yard. Transport from the plant storage yard to a remote installation site is normally by a flat-bed truck with motorized cranes again being used both at the on-loading and at the off-loading points. Accordingly, costly motorized crane equipment must be on hand at both the loading and remote unloading point with such equipment additionally incurring the high cost of a skilled crane operator. Additionally, manufacturers of concrete pipe are faced with the task of moving and storing same in an upright position to avoid distortion which otherwise occurs when newly formed conduit is stored on its side. An additional advantage of upright storage is the conservation of space. While the above mentioned problems are related to concrete pipe, similar problems are encountered in the storage and transport of other large monolithic structures such as utility vaults, manhole structures, etc.
Prior U.S. patents have disclosed various apparatuses for the transport of large structures each elaborating upon the advantages of horizontal transport from a vertical loading-unloading position. The examples of the prior art disclosures are found in U.S. Pat. Nos. 1,289,786; 3,674,166; 3,687,319; 3,848,758 all of which disclose apparatuses adapted for the transport of large monolithic articles while additional U.S. Pat. Nos. 2,189,052 and 2,308,648 disclose dump beds on which are carried aggregate loads. The aforementioned U.S. patents are mentioned simply as being exemplary of the prior art. For one reason or another, none of the known prior art apparatuses have apparently been received with a high degree of acceptance.